In primates the effects of (1) shock, (2) intravenous oleic acid injection, and (3) combination of (1) and (2) on the leakage of protein into the lung interstitium will be studied. Measures of lung mechanics, shunt fraction, A-a O2 and A-a CO2 difference and functional residual capacity will be made to determine correlation of these parameters with the various insults. Intravenous electrolyte solutions will be given in various doses to see if the abnormalities due to the above injuries are aggravated by fluid infusion using usual clinical doses and in excessive amounts of fluid. The protective effect of positive end expiratory pressure for the various combinations of insult and treatment will be assessed. A second group of studies will refine clinical methods of measuring lung mechanics using forced oscillation. Also we will assess the feasibility of substituting a fluid-filled for air-filled system of measuring esophageal pressure. The latter method will permit easy measurement of esophageal pressure in acutely ill patients and should improve the frequency response of the pressure measuring for forced oscillatory studies of lung mechanics.